


SweetFell

by idontevenknowugh



Category: Undertale (Video Game)
Genre: Angst, Fellcest - Freeform, First Time, Fontcest, Incest, M/M, Self-Esteem Issues, Soul Sex, Underfell, body image issues, failing at sex, fell bros being cute
Language: English
Status: Completed
Published: 2016-10-30
Updated: 2016-11-24
Packaged: 2018-08-28 01:33:34
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 3
Words: 8,077
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/8425555
Author URL: https://archiveofourown.org/users/idontevenknowugh/pseuds/idontevenknowugh
Summary: Sweet, fluffy Fellcest with a dash of angst. Not darkfic, I promise, like, really hard.





	1. Chapter 1

**Author's Note:**

> A short history of how this came to be:  
> asksanrustheskeleton said:Can you do a fellcest story plz I like your stories very much!!  
> Me: none ideas. O.o  
> Tarot Reading: A new relationship that makes good changes and is assured success. (WTF cards, why you gotta make me be nice to characters??)  
> My SO: Make it the most over-the-top sweet romance that you can.  
> Type: OMG YES FLUFF!!!  
> Me: Okay, but I'm probably going to make it sad.  
> \---------------  
> So this is me trying to make them sweet without deviating too far from their personalities. They both just really care for each other and want this to work. I hope the requester isn't too disappointed that this is a bit of departure from my normal themes. Haha. I think it's a nice flip of my tendency of making the Swap bros creepy.

“I LIKE YOU TOO,” Papyrus’s words reverberated through Sans’s skull as he attempted to translate them into something that matched his view of reality. He had been so sure, just a moment ago, that he had ruined everything with his frustrated, drunken declaration. Instead, Papyrus stood in front of him, a flush across those sharp cheekbones, fidgeting slightly and looking down at the ground. Sans felt his own blush break out at the sight. Papyrus, the monster who was always so proud, so strong, so demanding, looked so nervous. Over him?

“a-are you serious? you like me, like, more than a brother?” Sans asked. He had to make sure before his imagination got away from him. There could be all sorts of factors at play here. Papyrus, as confident as he was in himself, sometimes didn’t understand things quite right. Sans, being quite drunk, might not have been as clear as he thought he was.

“Y-YES,” Papyrus blushed harder, the stutter downright adorable coming from that sharp mouth. “I’VE LIKE- NO! I’VE LOVED YOU FOR A LONG TIME!” Papyrus’s face was set in determined lines, his meek demeanor fading as he talked. “I, JUST, I HAVEN’T KNOWN HOW TO SAY IT, AND YOU KEEP GOING TO THAT BAR AND IF ANYTHING HAPPENED TO YOU-” To Sans’s surprise tears appeared in Papyrus’s sockets. Sans flinched. He had fucked up. He had been fucking up a lot, hadn’t he? Walking forward, somewhat unsteadily, he wrapped his arms around Papyrus.

“northing’s going to happen to me, paps, especially with a cool monster like you looking out for me. m sorry I worry you,” Sans felt his own tears as they wet the front of his brother’s battle armor. “i didn’t think this was possible. i drink so i can forget just how much i love you, rather than burden you with the truth-”

“Your love isn’t a burden.” Papyrus spoke softly, encircling the smaller monster and pulling him closer. Sans snuggled into the security that was his brother.  
—————————  
The next morning, Sans woke up to a very upset Papyrus. The taller skeleton was storming his way through his morning routine, and Sans had a bad feeling that he had been at it all night. The house was unusually clean for the hour. His soul plummeted as he took in the evidence of Papyrus’s displeasure. Despite his hazy memories of everything going well, he had fucked it up last night, hadn’t he? Unfortunately, crawling back up to his room, like the low life he was, wasn't an option. He had work today, and if he had upset Papyrus, then skipping work would only escalate the problem.

“hey,” he tried, only for Papyrus to continue cooking as if he wasn't even there. Bracing himself, Sans fought back tears and prepared to try and at least repair their relationship as brothers. It might not happen right away. He had expressed some very uncomfortable feelings. Hopefully, some day, Papyrus would forgive him.

“about last night, sorry. i-”

“YOU SHOULD BE! G-GETTING MY HOPES UP LIKE THAT!” Papyrus interjected, turning furious and slightly wet sockets towards Sans.

“w-what?” Sans froze, the outburst so far from what he expected to hear that he couldn't find an appropriate response.

“YOU LED ME ON AND THEN LEFT ME ALONE. WHY, SANS?” He tried to wrap his thoughts around the statements, but he had been pretty far gone the night before. Did he mean-

“you’re upset because i didn't sleep with you?” Sans asked, shocked. “we just shared our feelings. i think that’s a bit fast, even for you.”

“WE DIDN'T HAVE TO…YOU KNOW, BUT I WANTED TO BE NEAR YOU AFTER…” Papyrus trailed off sadly and Sans felt a stab of guilt. He walked up and hugged Papyrus, relishing the way he felt his brother lean back into him.

“’m sorry, paps. i was, well, pretty drunk. the last thing i ever want to do is take advantage, and i’m not sure I could have stopped myself.” Papyrus turned to look at him, and he gave the other monster a squeeze.

“besides. our first time should be,” Sans flushed. Were they really talking about this? It hadn't been a full day. “i want to focus on making things work between us first. this relationship-” Papyrus turned fully, breaking Sans’s hug. He was staring down at him with those intense sockets, making Sans fidget. Was he assuming too much?

“This relationship…” Papyrus said it slowly, like he was trying the words out. “Are we…?” The uncertain expression tugged at Sans’s soul.

“i know last night was emotional, and if that’s not what you want, then so be it. if it is…then yes. nothing would make me happier,” Sans admitted, stepping back to give his brother room to decide. This was the moment. Both parties were sober, and it was out there, the chance to give this a go.

“OF COURSE! THE GREAT AND TERRIBLE PAPYRUS ALWAYS MEANS WHAT HE SAYS!”  
—————————  
Doggo slumped onto the stool next to the skeleton. He simply reeked of cheep beer. Sans had always envied flesh covered monster their ability to seal their noses against offending smells. Grimacing, he took a swig of his mustard and turned to the dog monster.

“Hey Sans, what’s with you and your brother?” Sans felt his eyelights shrink and his soul contract at the question. He snapped his skull down, glaring at his bottle in an attempt to hide his reaction.

“w-what do you mean?” he asked, fighting to keep his voice steady.

“Well, you guys have the weirdest thing goin’ on,” Doggo slurred out. “In the morning he’ll be givin’ you hell, then I see you guys chattin’ like it’s nothin’ during your rounds. He comes and drags you home every night, screaming match and all. Then the next day you’re tellin’ us all how cool he is an’ shit.”

“we’re brother. brothers fight,” Sans groused. Still looking at his drink. Thank goodness it wasn't about anything more than that. Still, he didn't need the reminder of how things had been before. They only did their normal Grillby’s display to keep the town from noting the most obvious change, Sans’s decreased alcohol consumption. Grillby had noticed, of course, but the flame monster kept his thoughts to himself.

“Naw, I mean, yeah, but it’s not, it’s not like that. He, I don't think he means it. The fights, I mean. It's more like…when kids pick on the monster they like, to get their attention. Not quite, but you see what I mean? Like, he wants your attention.”

“huh,” was all that Sans managed. Hearing it like that, and hearing from the monster himself that Sans’s bar trips left him feeling lonely and neglected, he could see it. Their fighting had decreased, but Sans never thought that they had only ever been his brother’s juvenile way of flirting.

They mostly avoided each other these days, an attempt to appear normal in public. The goal was to keep their budding relationship under wraps, so the brothers dodged the topic to the best of their abilities. Even relationships that weren’t taboo were fairly dangerous. Lovers were easily exploitable, and Sans was the weak point in theirs. Unfortunately, that was also strange. The Doggi kept giving Sans some strange looks, and Undyne had apparently remarked on Papyrus’s concentration, or lack thereof, more than once.

“So I guess I'm wondering, is he okay?” Doggo asked, intent on Sans. He shook himself from his thoughts.

“yeah, yeah he’s fine,” Sans assured the other monster. “it's not all that. mostly just posturing. he’ll come to me if it's anything serious.”

“Hm, alright. Wanna do shots?”  
—————-  
At home, they could do what they wanted, which turned out to be quite a surpassing experience for Sans. Papyrus, of all monsters, was a cuddler. He was very touchy overall, taking every chance he had to shed his glove and be in contact with Sans. The cutest thing was, in Sans’s opinion, when they settled down to watch MTT. The first time after their confessions, Papyrus sat down next to Sans and then slowly lowered his skull into Sans’s lap. Once there, he looked up at Sans with a nervous gaze. Sans smiled back and leaned down to kiss his brother with a clack. When he lifted his skull, Papyrus was blushing up at him, and his soul did a little twirl. It had become their standard TV night configuration, to his delight. He found the feeling of his brother there, being able to stroke his phalanges along his skull, soothing in a way he had never expected.

Bedtime was still a source of contention. Papyrus’s desire for physical contact warred with Sans’s anxiety that spending the night together would lead places they weren't yet ready for. The idea of sex was somewhat terrifying for him. Sans sure didn’t know what he was doing. He didn't know how much Papyrus knew, either, and he could not drum up the courage to ask. The thought of it left him flustered and blushing, which prompted questions from his brother, along with the insistence that he was being ‘unbearably cute’.  
———————-  
They had been dating for the past two months. Sans had fallen even deeper in love, something which hadn't seemed possible before. He learned, however, that the deep ache of love unfulfilled was nothing to the depths that spending his days surrounded by Papyrus’s loving touches, sweet smiles, and adoring kisses could send him. It was just that, the way his brother could make him feel like he was drowning and be all the happier for it, which got him in trouble. Plus, he caught Sans unaware during TV time, which Sans found supremely unfair.

“SANS,” Papyrus broached the subject during the fifth commercial in a row advertising MTT brand products, so Sans was more than ready for the distraction. He was lounging back fully into the couch, several phalanges idly touching Papyrus’s scapula. His sockets were lidded, but not heavy. He never fell asleep at these times, loath to miss a moment of this sweet intimacy.

“hm?” He responded, glancing down at his brother. Papyrus was looking up at him with that determined look he wore so well. Having it directed at him, here, of all places, meant only one thing. A talk. Talks weren't bad, per say. Often they went quite well. Papyrus had swept Sans off his feet even further by being surprisingly good at discussing their relationship calmly and rationally. As long as Sans communicated with some degree of clarity, that was. It had been uncomfortable, to say the least, to discover that his passionate and boastful little brother was markedly better at this than he was. Sans had yet to shed the anxiety and fear that years of hiding his feelings had instilled. He would repress everything, and then explode into a blubbering mess of emotions.

“I WANT TO SLEEP WITH YOU,” Papyrus said with a calmness that Sans would always envy. In contrast, just hearing the words made his skull heat and his eyelights shrink.

“bro, we’ve talked about this, if i spend the night-”

“THAT’S EXACTLY WHAT I WANT TO DO. I WANT US TO BE,” Papyrus flushed and looked away, which only increased Sans’s panic. “MORE INTIMATE.” Papyrus’s own reservations showed through in his word choice. Still, his jaw was set.

“are you sure-” Sans didn't get a chance to say any more as Papyrus smoothly raised himself up onto his arms, turning his upper body, so that he could kiss Sans. Their tech clacked, but then something soft brushed along his teeth as it stole into his mouth, making them tingle. It ran, somewhat shyly , along the inside of his mandible. That was probably for the best, as it allowed Sans to catch his bearings and focus on forming his own approximation of a tongue. With no small amount of anxiety, he brought it forward to meet Papyrus’s.

The tingly sensation moved through his magic to his soul, and from there was distributed throughout his body. His bones felt like they were vibrating, a buzzing sensation that, rather than troubling, imbued him with an energy Sans didn't know he was capable of. He brought his arms up, one wrapping around Papyrus’s cervical vertebrae, the other resting his phalanges on the back of the taller monster’s skull. Pulling his brother closer, he put that energy to good use, exploring Papyrus’s mouth in its entirety. Every time his magic brushed up against his brother’s, a fresh wave of urgency hit him. Tasting, feeling, holding Papyrus…it was downright addictive.

It wasn't until Papyrus moaned into him that Sans realized he had been basically ravaging the other’s mouth. Embarrassed and horrified he dropped his hold and disentangled their jaws, pulling back with gasp. Papyrus was still suspending his torso above Sans’s lap, his legs stretched out across the couch, and he was, to Sans’s chagrin, panting.

“S-SANS?” His name was uttered in a slightly husky, breathless tone that made the excited buzz of his magic settle in his soul uncomfortably. Nonetheless, he picked up a slight undercurrent of uncertainty that made his mind kick back into action.

“sit,” his voice cracked, and he willed his magic to settle before trying again. “sit up, that can't be comfortable…” he trailed off as Papyrus applied his own logic to the suggestion. With an astounding lack of effort he curled his long legs under his torso and pushed himself up onto his knees before swinging one over Sans’s femurs and settling himself on top of them. With lidded sockets and a soft smile, he began to move his skull forward. Ignoring the reawakened hum of excitement emanating from his soul, Sans brought his phalanges to his brother’s scapula and held him back.

“hold on, we should talk about this.”

“WHY? SO YOU CAN AVOID IT? WHY DON’T YOU WANT TO HAVE SEX WITH ME?”

“i- i do want to have sex with you! i just, i don't want to take advantage of you!”

“HOW COULD YOU POSSIBLY BE TAKING ADVANTAGE OF ME?” Papyrus asked, clearly affronted by the idea. Sans threw his arms up, frustrated.

“what do you know about sex, paps? honestly, what do i know about it? if i did anything to hurt you, to hurt our relationship, i wouldn't be able to forgive myself.” Sans declared, his voice slowly raising through the words as all of the frustration and anger began to pour out of him. “i'm terrified!”

Silence fell over the brothers. Sans’s mind regained control as his emotions ebbd. He could just about smack himself. What a stupid fucking thing to say, but there was no taking it back now. It was done. Sans waited, feeling awkward and stupid. Papyrus finally opened his mouth and he tensed.

“I WANT TO DO THIS WITH YOU, SANS. YOU AREN’T GOING TO HURT ME. YOU’RE RIGHT, I DON’T KNOW MUCH ABOUT SEX, BUT WE CAN FIGURE IT OUT TOGETHER.” Sans barely bit back a very inappropriate laugh. It was such a simple solution. He was so used to spending his time worrying about Papyrus. Sans did everything he could to protect his brother and his feelings. Even in their relationship he had been babying the other monster.

Sans looked down, blushing, only to be confronted with the realization that their pelvises were mere inches apart. Fuck, had they just had a fight in such an intimate position? There was something really wrong with him. He had the love of his life, his sexy, sweet Papyrus in a position like this, and he goes and starts a fight with him. Speaking of…

“papyrus, why are you sitting like this?”

“THIS IS HOW PEOPLE MAKE OUT, OBVIOUSLY. I THOUGHT YOU WOULD KNOW THAT MUCH. CLEARLY I WILL HAVE TO TEACH YOU WHAT I KNOW,” Papyrus was leering at him, and Sans blushed harder in the face of such a candid statement. He was completely outmatched, wasn’t he?


	2. Chapter 2

**Notes for the Chapter:**

> Ah, I know. This is kinda sad. (I have to make Sans sad. It’s in my contract.) I promise, with everything I’ve got, that the next part will be better. -hopeful smile-

His anxiety on full blast, Sans followed Papyrus into his room. His monster truck bed, never a source of concern before, felt now like the instrument of Sans’s destruction. He had agreed to this, technically. He had been under some amount of duress, technically. He understood why his brother had pushed, though.

Exploring sex together sounded like a good idea on paper, but all he could think about was how badly it could go. Things could end awkwardly, scaring their relationship and making it putter out. What if he pushed too hard and Papyrus ended up hating him. Even worse, what if Papyrus said nothing and let Sans do something he didn’t want. Sans not only could, but was likely to disappoint his brother. Someone could get hurt and… Why were they doing this again?

Sans had plenty of good dreams, very good dreams, about Papyrus. He flushed just thinking about some of the things his mind came up with. He just wasn’t confident that those dreams could become reality. Still, he needed to calm down and get in the mood, so he recalled a recent one, his brother arched over him, telling him he looked- well that was a fantasy for sure. No one would call his wrecked frame beautiful. Crap!

He couldn’t even remember the last time Papyrus had seen his ribs. They were nothing like when he was younger. Sans flushed at the thought of exposing his ugliness to Papyrus. Would he be disgusted? Sans’s mind scrambled, trying to find an excuse to stop this before it ever got that far, but nothing came to him. Well, nothing that wouldn't hurt Papyrus, and Sans would much rather Papyrus reject him than ever give his brother the impression of the reverse.

So he sat, uncomfortable and silent, on the bed as Papyrus undressed. Sans was pretty sure that his brother wasn’t trying to put on a show, but he found his eyelights glued to the display anyways. Purposeful or not, the way the tall skeleton was slowly exposing his bones drove Sans wild, pulling him from his thoughts. Eventually, however, Papyrus finished, standing in front of Sans fully naked and slightly flushed. Perfect.

“Sans! You need to, also,” Papyrus looked away, as if embarrassed to ask. Sans flushed himself, the mere thought of it making hyper aware of the flaws already on display. His tongue flicked absently over the gold tooth, and he barely kept himself from running his phalanges over his skull. Papyrus had overlooked those, but this was make or break time. He would see just how ugly Sans had become over the years. Sliding off his jacket, he set it aside. His shorts fell to the ground with little fanfare. His shirt, however, he fiddled with, trying to build up the courage to remove it.

Phalanges touched his own, startling him. Papyrus, red still staining his cheekbones, gripped Sans’s phalanges, tightening them around the fabric and pulling them up. The t-shirt drew up, exposing every crack and scar. Sans couldn’t help himself and looked to the side, unwilling to watch Papyrus’s reaction. He had to fight off tears, his bones rattling with the effort.

“Sans…,” Papyrus breathed his name as the shirt finally cleared his skull. He was laid bare. His phalanges were released and fell limp, the garment falling to the floor with a soft thump. A bare phalanx touched Sans’s sternum before tracing along one of the ribs. His shaking increased, bones tense as he waited for Papyrus’s shock to fade into-

“Why didn’t you tell me!” His brother’s voice broke, making Sans looked up at him in surprise. Papyrus was staring down at his rib cage, tears dripping steadily down his skull.

“it was a forever ago,” Sans muttered. He grabbed Papyrus’s phalanges and held them still them where they were worrying over the three warped ribs, “we didn’t have the gold for a healer, and you were too young to-”

“So you didn’t set them?” There was a hint of the anger he had expected even though Papyrus’s still spoke quietly. What he hadn’t expected was for the tears to increase. Sans flinched. “I would have done it!”

“i couldn’t put you through that!” Sans felt his own anger stir. “look, i’m sorry! i’m sorry i didn’t warn you. i know that it’s ugly and hard to look at! i never should have let things get this far.” Sans’s vision grew blurry as he let go of Papyrus’s phalanges and reached down for his shirt. This was all a big fucking mistake.

Sans didn’t get the chance to cover up, Papyrus wrapping him in those long arms. The force of the movement pushed him back a few steps until his fibulae hit the bed and he fell backwards. Papyrus fell with him. Sans paniced slightly as found himself being squeezed against his brother’s broad rib cage, their nakedness alarming in a whole different way now.

“YOU AREN’T UGLY, AND YOU WILL NEVER TALK LIKE THAT AGAIN!” Papyrus’s voice was thick and heavy, reverberating against Sans’s skull where his brother’s jaw rested. “I LOVE YOU, AND THIS DOESN’T CHANGE ANYTHING.” He released Sans, lifting himself up on his arms to look down at the stunned monster. Tears dripped down to splatter gently against Sans’s skull. “I JUST WISH YOU HAD LET ME HELP. YOU SHOULDN’T HAVE HAD TO DEAL WITH THAT ALONE! I’M HERE FOR YOU, SANS! I ALWAYS HAVE BEEN, AND I ALWAYS WILL BE, YOU IDIOT!”

Sans felt emotion wrack his body, his ribs shaking with the force of it. He brought his arms up to try and cover his sockets, embarrassed as his feelings once again took over. The bed shook as Papyrus pushed himself to standing. He slipped one arm under Sans’s cervical vertebrae and the other under his femurs, lifting the smaller skeleton easily. Sans didn’t fight it, the feeling of being held against Papyrus’s perfect rib cage wonderfully solid. A slight rattling clack started as Sans shivered against his brother.

Fuck, he wanted nothing more for the tears to stop, but they just kept coming. He fought off the urge to give in completely until it came out as a loud sob, a gasp, and a series of hiccups. Why did he always hiccup when he cried? He didn’t even have a diaphragm for crying out loud. Papyrus sat down on the bed, swinging his legs up and laying down. He shifted Sans so they were laying next to each other. He pulled Sans up so that his skull was resting on Papyrus’s ribs. Sans weakly tried to move off of him, but a firm arm kept him in place. It couldn’t have been comfortable to have Sans’s tears dripping down between his ribs, but Sans couldn’t stop them long enough to say so.

He resigned himself and let his eyelights rest on his brother’s bright, steady soul through the gaps in his ribs. Long phalanges drifted up and down his spine, the touch relaxing him as the last of his tears fell. Completely drained, Sans fell asleep surrounded by Papyrus.   
——————————  
Papyrus kissed him, pulling his attention into the electric touch of magic on magic. Sans went willingly. He tensed slightly as he felt his brother lift the hem of his shirt, but Papyrus didn't stop the kiss. Without removing the garment, he began to stroke and rub Sans’s ribs. The smaller skeleton melted into the touches, bones alight with that buzzing hypersensitivity. When he reached the deformed ribs Papyrus’s touch became light, as though the wrong move would break them all over again.

“don't worry,” Sans broke the kiss himself and murmured the words into Papyrus’s mandible, “long since healed.” Papyrus responded with a probing touch right on the fracture point of the lowest one. Sans gasped at the touch, an alternating current of sensations radiating. The phalanx withdrew immediately.

“Did I hurt you?” Papyrus’s voice was quiet, but full of urgency. Sans shook his skull, the motion very lightly scrapping their teeth against each other in a way he didn't dislike.

“just feels…weird,” Sans supplied, unable to give the sensation a name. After a pause, Papyrus nodded. The touches resumed, Papyrus avoiding the scars. Sans quickly lost himself in a sea of gentle shivers and breathy moans, in those brief moments his mouth was unoccupied.

Papyrus pulled away, leaving Sans a gasping mess where he had been pushed up against the bed sometime during the proceedings. He gave Sans a meaningful look as he took hold of the bottom edge of Sans’s t-shirt. The smaller skeleton froze momentarily before he resolutely nodded. With a solemn air, Papyrus removed the garment. Sans flinched, which he felt was not all that bad, in comparison to his urge to snatch the blanket of Papyrus’s bed and cover himself.

There was a moment of stillness where Papyrus just stared at him. Even through his anxiety, Sans could see the adoration in that gaze, and flushed. Emotion threatened to overwhelm him all over again, if this went on much longer. He reached for Papyrus and pulled him in for a deep kiss, pouring everything into the way he clutched at the taller monster, phalanges holding his clavicle and slipping behind his cervical vertebrae.

Papyrus moaned and pressed a femur forward, slipping it between Sans’s. It brushed gently against his pelvis and he tensed, sharp spikes of pleasure running up his spine. His brother seemed about to pull away, but Sans couldn't have that. He needed more of that feeling. One set of phalanges released their grip on his brother’s clavicle and moved down to Papyrus’s iliac crest. Sans pulled at the same time he thrust forward, pressing Papyrus’s femur against that spot again, but harder. A hum traveled through their connected mouths, and the femur ground into Sans’s pelvis. He had to break the kiss to let out a loud groan, arching into the pressure.

“Fuck, Sans,” Papyrus panted, “you’re driving me crazy.” The taller skeleton pushed Sans back so he was laying on the bed and began to lick him. Everywhere. Shit, when had his brother become so talented with that thing? Sans devolved into a mess of moans and gasps. Every touch from his brother was like a shock of electricity, sending Sans’s soul into convulsions. The pleasure was so strong it made his bones positively ache. His magic flared up, seeking an outlet. Papyrus’s tongue lathered attention across his clavicle, down his ribs, slowly sinking to his knees as he moved down Sans’s body. He paused at his pelvis, though. Sans tried to get his bearings, the hum of pleasure fading slightly so he could think. It didn't last, though, as Papyrus licked up his pubic symphysis. Sans screamed, pelvis arching up, as his magic flared white hot.

“SANS!” Papyrus sounded angry, pulling Sans prematurely from the pleasant haze he found himself in. Looking around to see what was wrong, he sat up, only to feel liquid run down his spine and the inside of his ribs. It dripped down onto the ones below, cooling as it went. The sensation made him whimper. Instantly, Papyrus was looking him over for injury.

“ARE YOU ALRIGHT?” He asked, peering into Sans’s ribcage. “YOUR SOUL LOOKS… WEIRD.” Sans could tell that his brother was worried, but Sans still hesitated to answer. It was embarrassing to admit it, even to himself. He flushed and looked away.

“’m fine, bro,” He said. The words were met with an expectant silence. “sanorgasm...” His skull must be positively glowing by now.

“YOU, YOU… FINISHED… ALREADY?” Papyrus didn’t hide the confusion, or the disappointment, from his voice. Sans’s euphoria fled in the face of it. Oh shit. He had fucked up, leaving Papyrus unsatisfied. Sans pushed himself up from the bed.

“i could-” He offered, hoping to salvage the night.

“I’M NOT IN THE MOOD,” Papyrus didn’t even let him finish, instead gently shooing him away the bed and began to strip the comforter off. Sans saw several red splotches, from him, he supposed. Shame reached every edge of his soul at the sight.

“papyrus, i’ll clean it, at least,” Sans tried again, setting phalanges on his brother’s humerus. Papyrus paused and looked at him. Sighing, he leaned down and kissed Sans, a chaste touch of teeth against teeth. It didn’t really make Sans feel better, but he leaned into the touch anyways. It was far better than getting the cold scapula.

“IT’S FINE, SANS. YOU HAVE WORK IN THE MORNING. GO GET SOME REST.” Papyrus said and turned back to the bed to see if any had seeped through. Sans nodded, scapulae sagging.

“sorry, bro,” Sans muttered, and shuffled back to his room.


	3. Chapter 3

**Summary for the Chapter:**

> Sans wants to make everything right, and the Fell bros jump their first big relationship hurdle.

**Notes for the Chapter:**

> My Thanksgiving feel-good offering of sin. Thank you for all your feedback on this fic. I'm glad I could mostly not fail at the fluff!

Sans grumbled to himself and checked the door one more time. The house was silent, an impossibly, if Papyrus had been home. He had scoured the UnderNet and the library, but there was little to no information to be found about sex, for monsters who lacked traditional genitalia. Papyrus’s plan of figuring it out together _sounded_ good, but their first attempt had failed and hurt Papyrus. Sans had failed and hurt Papyrus. He wouldn’t let that happen again.

Taking a deep breath, he removed his shirt and laid down on his mattress. Shaking phalanges lifted and came to rest on his rib cage. With a flush of embarrassment, he began to stroke along the bones, studiously avoiding his warped ones. The break in the normally smooth curve was still a sore spot for him. Heh. Still, his phalanges caught on a number of poorly healed cracks as traversed along his bones. He tried to ignore the reminder of how broken and ugly his body was.

It was a struggle to let his mind wander and ignore the anxiety that threatened to take hold. When he managed, though, it felt nice. Even the tiny pricks of pain from the scars felt kind of good, the pain contrasting nicely with the pleasure. He could feel himself heat up as he continued. Eventually he found that his floating ribs were incredibly sensitive, but if he stroked along one for too long, the sensation started to become overwhelming, and kind of painful. His sternum, also, drew gasps from him as he stroked and scraped at it. The underside was more sensitive, but much harder for him to work with, so he filed that away for later. He would have to see what Papyrus liked.

His phalanges kept twitching towards his pelvis, but he held them back. This was supposed to be different from his habit of rubbing one out as quickly and as quietly as he could, while trying to hide his urges from Papyrus. No, this was about taking his time and finding out what made him feel good. Sans needed to figure out how to turn his urges from something to be rushed to an experience, to be savored between him and Papyrus.

He redirected one set of phalanges towards his spine, which felt amazing, especially when he ran his sharp claws along the disks of his spine. The pain and pleasure combo that Sans had enjoyed previously was amplified, making him arch up off the bed and gasp loudly. He immediately paused, listening for any sigh that Papyrus had come home while he was occupied, but there was nothing. He shook his skull, berating himself for his paranoia. His brother had training today, and he never missed training.

Resisting the urge to hurry things along, Sans returned his phalanges to his body, stroking ribs and squeezing vertebrae. His pleasure grew slowly, until he couldn't resist. One hand slipped down to rub along his pubic crest. Shit, that felt so much better than when he rushed. He could only imagine what it would feel like when Papyrus was touching him. Even better, Sans started to imagine his brother’s expressions as Sans stroked and rubbed him. Fuck, he loved the idea of his proud little brother completely losing himself at his touch.

After what happened, Sans really liked the idea of taking care of Papyrus. Fuck, his brother didn’t even know what an orgasm looked like. He would make sure his brother felt amazing. Getting to see his brother lose control was just the icing on the cake. The thought of what Papyrus might look like as he did so aroused him even further, and he felt his soul pulse. With one digit rubbing his pubic symphysis and one hand roaming his ribs and spine, Sans came to the image of his brother moaning and gasping beneath him.  
————-  
Deciding to do something and then doing that thing were vastly different. Every time Sans thought he had found his nerve, it abandoned him at the last moment. So far he had asked Papyrus if he wanted to have sentences, sentries, and secrets. His brother was starting to give him…looks.

Besides that, though, Papyrus had gone back to life as normal. He didn’t say a single thing about Sans’s failure in the bedroom, or even about trying again. He still leaned down to give Sans kisses each morning, and he still laid down and put his skull in Sans’s lap when they watched TV. The only one being awkward was Sans.

Despite knowing full well that Papyrus would love to try again, Sans couldn't help but feel a wave of anxiety whenever he thought about the subject. It wasn't even the same anxiety he’d had before. Worrying about whether they were ready for sex or not had been replaced by concerns about his own preparedness and ability to perform.

One night, as they kissed before going to bed, Papyrus pulled him in for a tight hug. Sans hugged him back, relishing the contact, like always. Phalanges ran up and down his spine, comforting rather than sensual, but Sans shivered as one phalanx caught on a ridge and pressed into a disk. This was a great chance, and he should take it. While he tried to find the perfect words, Papyrus began to pull away. Sans panicked.

“want to, um, try?” He blurted out. Papyrus paused and gave him a confused look. Sans shrunk down, looking away. “s-sex. want to try…again?”

“Do you, really, want to?” Papyrus asked quietly. Sans looked up at him and found that his brother was now looking away, more miserable than Sans had ever seen him. His own anxiety was pushed to the side by his concern. What had he done? Had he screwed everything up way worse than he thought?

“of course I do,” Sans asserted, though he had to wonder, “why wouldn't I? Do you not-”

“NO, I WOULD LIKE TO TRY AGAIN AS WELL.” Papyrus jumped in, stopping Sans’s question in its tracks. “I WAS…UNKIND. LAST TIME. AFTERWORDS.” Sans stared as Papyrus turned bright red, “I’M SORRY.”

“naw, bro,” Sans felt tears threaten. “i’m sorry. i failed-” he was cut off again as Papyrus swept him up in another hug. He felt his bones creak as the taller skeleton squeezed him with all of his impressive strength. It caused a good kind of ache, though, as he enjoyed the ferocity of his brother’s feelings for him. The tears came, but they were welcome. He clutched at Papyrus in return.

No one spoke, the press of their bodies together enough for several long moments, but eventually, Papyrus released Sans and immediately turned to his room. Sans barely caught the subtle way Papyrus rubbed his sockets as he did so. Smiling faintly, Sans stepped forward and pushed gently at his brother's rib cage.

Papyrus paused and looked back at him, but when Sans didn't offer any explanation, he gave in and led the way into his room. Sans steered the other monster over to his bed and then tugged on his radius softly, prompting him to sit.

“do you want to try now?” Sans asked, already starting in on Papyrus’s armor. If his brother said no, then Sans would just tuck him into bed, and that would be that. However, there wasn't a reply. Papyrus was looking away again, stiff and awkward. Sans let his phalanges drop.

“it's okay if you don't. sorry,” Sans flushed, his eagerness banked. What was he-

A strong grip on his shirt pulled him up into a searing kiss. Startled, he made a noise of surprise before enthusiastically reciprocating. Sans wrapped his arms around Papyrus, pulling himself closer and folding up his legs to straddle his brother’s lap on his scapula. This kiss was more than a kiss. Sans’s body moved along with the tangling of their tongues, ribs rubbing up against Papyrus’s through their shirts. By the end, he was gasping and his self control was swiftly slipping away. With a growl he pushed Papyrus back, the taller skeleton falling onto the bed with a shocked expression.

“yes or no?” he asked, leaning down to stare Papyrus in the sockets. Papyrus just stared up at him, expression thoughtful. Sans flushed under the scrutiny and was about to draw away when his brother finally spoke.

“Yes,” phalanges brushed along Sans’s skull and he leaned slightly into the touch. Papyrus’s voice was soft and full of need. Slowly, a grin spread across his skull. Now was the chance to see his fantasies become reality.

He began by taking off Papyrus’s battle armor. Along the way, he made sure that his phalanges dragged along each and every one of his brother’s ribs. He delight in the way he could feel Papyrus shiver under him, against his pelvis. As the garment was finally pulled away, he found a light blush had spread across Papyrus’s sharp cheekbones. His magic heated further at the sight. Fuck. He couldn’t rush this. Pulling upon all of his willpower, Sans focused on the task he set out to do. Make his brother feel amazing.

With shaking phalanges, he began to trace along the exposed bone, drawing forth more of those shivers. For a while he just lost himself in the wonder of exploring his brother’s body. Remembering the sensitive underside of his sternum, he ran a phalanx along it gently. Papyrus gasped. Smile stretched large enough to feel silly, Sans scratched harder along the bone and felt a thrill move through him at the loud moan it wrenched out of the taller skeleton. He gave it a few more passes before moving on. There was still so much to try.

He wrapped a hand around one of his brother’s floating ribs and pulled. The most amazing choked gasp, and the feeling of Papyrus grinding up into him, was his reward. With a vicious little smirk Sans gripped and twisted his phalanges around the sensitive bone. The reaction was instantaneous and oh so rewarding. Papyrus bucked under him, and Sans couldn't help himself. He ground down into the sensation, letting out a moan of his own.

“Fuck, Sans,” Papyrus moaned, and Sans had to take a moment to appreciate that the vision before him. His brother, his proud strong brother, was flushed and panting. The comforter was bunched in his phalanges, and he was fidgeting slightly. Sans could feel him thrust up slightly every once in a while. Eyelights dimming and smile shifting to what he hoped was a sultry look, he ground down again.

“Ah!” Papyrus thrust back with more urgency, and Sans began to notice a red glow forming from within his brother’s rib cage. His anxiety swept back onto the scene. Was that, was that Papyrus’s soul? This hadn’t happened when he was doing it on his own, or even during their last attempt. He reached out and brushed along the ribs near the sternum, where the glow was strongest.

“Yes, there!” Papyrus cried and arched his ribs up into the touch, startling Sans. The glow brightened, and he felt his own magic react. He almost let it have its way, but resisted at the last minute. Pulling out another monster’s soul was an act of aggression. Was it really the right thing to do here? His phalanges hovered over Papyrus’s rib cage, stripes of red light shining across them.

“Sans?” His eyelights snapped up to Papyrus’s sockets. The flushed monster grew serious, pushing himself up onto his elbows. The motion pushed his ribs against Sans’s phalanges, and Sans pulled back like he had been burned. Concern wiped away all signs of their activities as Papyrus took in the motion.

“What’s wrong?” He asked, voice shaking. Sans couldn’t tell if it was fear, anger, or arousal, though he noticed that the glow of Papyrus’s soul was slow to fade. He collected himself. No, he was not going to fail his brother again. He had to do this right.

“paps, your, um, your soul,” He looked down at the glow and moved both sets of phalanges to rest on the bone above it, reverently. His thumbs stroked lightly along Papyrus’s sternum. “can I?”

His brother’s expression shifted to shock as he realized just what Sans was asking to do. He had learned the rules of the Underground. Shit, Sans had taught him those rules. There was no way he could trust Sans enough to-

“YES,” there wasn’t one bit of uncertainty in Papyrus’s voice. Sans’s phalanges curled around the other monster’s ribs, slipping into the gaps, as he tried to steady himself. He was excited. He was euphoric. He was terrified. Papyrus was moaning. Sans was jolted out of his thoughts by his brother tossing his skull back and moaning in a way that shot straight through his self control.

He pressed Papyrus back down firmly and let his magic have its way. It rushed through the contact between them, seeking out the source of that intoxicating glow. When it found it, Papyrus’s magic responded with enthusiasm. With a soft, intimidating ‘ting’, his brother’s soul appeared, the red glow that had been muted by Papyrus’s ribs now bathing Sans in light. For a moment, he couldn’t do more than stare. It was beautiful.

“paps….” He breathed, and brought trembling phalanges up to the floating soul. He hesitated, mind screaming at him that he shouldn’t. He was going to fuck up. He was going to hurt Papyrus. This was his soul for fucks sake. Ignoring the anxiety, he gently took the soul in hand, not willing to stop now and throw Papyrus’s trust back in his face. Sans just had to be careful.

He rubbed the soul lightly, the strength of Papyrus’s moans startling him. His own soul was thudding in his chest, and he felt warm. Keeping up the gentle massaging motions, Sans tried to figure out what to do next. Papyrus clearly liked having the bundle of magic touched, but how far was too far? Something…something gentle. Could he? Should he? Trembling with a heady mixture of arousal and anxiety, Sans lifted his phalanges.

Papyrus screamed, thrusting up with his all too impressive strength, as Sans’s tongue touched the soul. Sans rode the motion in blissed out silence as he savored the magic on magic contact. He felt like he was drowning in pure Papyrus. Distantly, he felt tears prick his sockets at the overwhelming sensations, but a huge wave of love and trust crashed into him, keeping him from the physical world. Sans gasped as the intensity of Papyrus’s emotions threatened to carry him away.

Emboldened by the reactions so far, Sans licked more firmly along the soft, warm surface of the soul. Papyrus clutched as his femurs, holding him in place as the taller skeleton ground their pelvises together. The contact was pleasant, but paled in comparison to the feel of their magic. Sans focused on that, practically lathering attention on the soul until he started to notice a sharp, tangy flavor begin to develop. As it grew a heat, not the same but also not dissimilar from his favorite spicy mustard, began to coat his tongue. It was painful, and yet he couldn’t help but find it downright addictive. He pulled the soul into his mouth and suckled, chasing more of that taste.

Papyrus spasmed beneath him, shouting, and a rush of liquid flooded his mouth, startling him. He swallowed, trying to get it all down, and Papyrus’s shouts turned to screams. It was too much, and Sans felt the syrupy juices slip out between his slightly parted teeth and dribble down his mandible. The soul was hot and heavy on his tongue. Fuck, the soul. Carefully, but urgently, he spit it out onto his phalanges, making Papyrus jerk and groan.

Breathing heavily, Sans watched as Papyrus, skull bright red, twitched on the bed, coming down from what must have been one hell of an orgasm. His brother’s sockets were dark, his teeth parted as he panted and moaned. Drips of his own cum fell from Sans onto his rib cage and spine, but he hardly seemed to notice. Sans shook as he moved to deposit his brother’s soul back into his rib cage. As it was gently pulled from his grasp and into place, Papyrus let out a little sigh. Sans glanced at him in time to see the most amazing smile, soft and satisfied, across the taller monster’s skull.

His own soft smile tugging at his jaw, Sans leaned down and kissed his lover. Shit, he could say that now. His skull heated, and he became aware of just how awkward the position they were in was. He moved one leg back, unfolding it, followed by the other, so he was standing beside the bed. His legs immediately tried to give out, stiff after kneeling for so long. He grabbed the edge of the bed to steady himself. Papyrus was mostly laying on the bed, but his knees were folded over the side, feet on the ground.

“turn,” Sans’s voice felt hoarse and thick, mouth still coated in his brother’s release. His flush darkened. “get on the bed,” he added, absently rubbing his tongue along the his hard palate. Papyrus sat up, looking dazed but happy, and did just that. Sans quickly dropped his jacket and removed his shoes, and for once his brother said nothing. Sans climbed into the bed and tucked himself up against Papyrus’s broad frame. He could feel the slightest tremors as they still played out across Papyrus’s bones. His phalanges wandered the exposed rib cage, but very softly. Soothing, rather than pleasuring. Papyrus’s arm wrapped around his scapulae and pulled him in tight.

“Sans, that was…you’re…it was amazing.” Papyrus finally said, his deep rumble soft and relaxed. “Should I-”

“naw, pap,” Sans knew what he was about to ask, the situation mirroring their last attempt, but yet so vastly different. This had been Sans’s goal all along, to put everything into his brother’s pleasure. He had succeeded, and he felt more satisfied now than after any orgasm he had managed on his own. His soul was pleasantly swollen with love and contentment, bringing his brother to the heights of pleasure a euphoria all its own.

“just enjoy it,” he added, and pushed himself up in order to kiss Papyrus. The taller monster opened his mouth, accepting the kiss, before suddenly pulling his head back with a jerk. Sans was left with his tongue out and a surprised expression on his skull.

“wha-” he started to ask.

“Did I just kiss you while you had my…you know…on your mouth?” Papyrus’s expression was slowly growing horrified, in that way he regarded any kind of mess. Sans just stared at him.

“yes,” he said, uncertain why Papyrus would be squeamish about his own release. He didn’t get a chance to ask.

“Gross! Go clean up!” He was shoved out of the bed with surprising gentleness. Sans stood grudgingly and began to shuffle towards the door. He glanced back to see the most amazing sight in the world.

Papyrus had laid back down, still shirtless, with one arm behind his skull. He was giving Sans a fond smile, the like of which he had never seen before. Emotion had tears pricking at Sans’s sockets. They had gotten through one issue as a couple, and a big one. It was likely one of many, many more, he had to admit. His anxiety was never going to magically go away, and he had spied hidden insecurities deep in his brother’s soul. He smiled back at Papyrus. He knew they could do it. They could get through anything, together.

**Author's Note:**

> http://idontevenknowwhattoputhereugh.tumblr.com/
> 
> My tumblr is where I: take requests, chit chat, post teasers for these fics, reblog a lot of skeleton porn, pimp all my favorite fics


End file.
